I had a friend in Vancouver who was into building and overclocking computers. And I mean seriously overclocking them. He told me, once, that if any of the seven case fans in his system died, he had to shut down his PC or it would overheat.
Well, the inevitable happened, one day, and Brandon went a little too far in overclocking a video card...burned it right out. Brandon went out and bought two video cards ($300 apiece. Construction jobs paid well) to replace the one he fried. When grilled him about the second card...why would you buy two, do you even need the second card? His reply was "No. But I might."
Do you need a lathe that big? "No...but I might." =)